Added functions to get a certain number of primes

This commit is contained in:
2021-03-10 12:23:03 -05:00
parent 1c47477213
commit 81fa373255
2 changed files with 124 additions and 5 deletions

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@@ -1,10 +1,10 @@
//typescriptClasses/Algorithms.ts
//Matthew Ellison
// Created: 10-19-20
//Modified: 10-19-20
//Modified: 03-10-21
//This class holds many algorithms that I have found it useful to keep around
/*
Copyright (C) 2020 Matthew Ellison
Copyright (C) 2021 Matthew Ellison
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
@@ -218,6 +218,107 @@ export function getPrimesBig(goalNumber: bigint): bigint[]{
return primes;
}
export function getNumPrimes(numberOfPrimes: number): number[]{
let primes: number[] = []; //Holds the prime numbers
let foundFactor: boolean = false; //A flag for whether a factor of the current number has been found
//If the number is 0 or negative return an empty list
if(numberOfPrimes <= 1){
return primes;
}
//Otherwise the number is at least 2, so 2 should be added to the list
else{
primes.push(2);
}
//We can now start at 3 and skip all even number, because they cannot be prime
for(let possiblePrime: number = 3;primes.length < numberOfPrimes;possiblePrime += 2){
//Check all the current primes, up to sqrt(possiblePrime), to see if there is a divisor
let topPossibleFactor: number = Math.ceil(Math.sqrt(possiblePrime));
//We can safely assume that there will be at least 1 element in the primes list because of 2 being added by default
for(let primesCnt: number = 0;primes[primesCnt] <= topPossibleFactor;){
if((possiblePrime % primes[primesCnt]) == 0){
foundFactor = true;
break;
}
else{
++primesCnt;
}
//Check if the index has gone out of bounds
if(primesCnt >= primes.length){
break;
}
}
//If you didn't find a factor then the current number must be prime
if(!foundFactor){
primes.push(possiblePrime);
}
else{
foundFactor = false;
}
}
//Sort the list before returning it
primes = primes.sort((n1, n2) => n1 - n2);
return primes;
}
export function getNumPrimesBig(numberOfPrimes: bigint): bigint[]{
let primes: bigint[] = []; //Holds the prime numbers
let foundFactor: boolean = false; //A flag for whether a factor of the current number has been found
//If the number is 0 or negative return an empty list
if(numberOfPrimes <= 1){
return primes;
}
//Otherwise the number is at least 2, so 2 should be added to the list
else{
primes.push(2n);
}
//We can now start at 3 and skip all even number, because theyu cannot be prime
for(let possiblePrime: bigint = 3n;primes.length < numberOfPrimes;possiblePrime += 2n){
//Check all the current primes, up to sqrt(possiblePrime), to see if there is a divisor
let topPossibleFactor: bigint = sqrtBig(possiblePrime);
//We can safely assume that ther ewill be at least 1 element in the primes list because of 2 being added by default
for(let primesCnt: number = 0;primes[primesCnt] <= topPossibleFactor;){
if((possiblePrime % primes[primesCnt]) == 0n){
foundFactor = true;
break;
}
else{
++primesCnt;
}
//Check if the index has gone out of bounds
if(primesCnt >= primes.length){
break;
}
}
//If you didn't find a factor then the current number must be prime
if(!foundFactor){
primes.push(possiblePrime);
}
else{
foundFactor = false;
}
}
//Sort the list before returning it
primes = primes.sort(function(n1, n2){
if(n1 > n2){
return 1;
}
else if(n1 < n2){
return -1;
}
else{
return 0;
}
});
return primes;
}
export function getFactors(goalNumber: number): number[]{
//You need to get all the primes that could be factors of this number so you can test them
let topPossiblePrime: number = Math.ceil(Math.sqrt(goalNumber));